Blocked nose: what causes nasal congestion and how is it treated?

Most people experience nasal congestion, commonly referred to as a blocked nose. It is usually caused by an infection, such as the flu, a cold or coronavirus. 

However, frequent or persistent episodes of nasal congestion can be a symptom of other conditions, such as allergic rhinitis, a deviated nasal septum, nasal polyps, swollen adenoids, chronic (long-term) sinusitis and in rare cases, tumours.

Causes of nasal congestion


When you catch a cold, flu or coronavirus, the lining along the inside of your nose (nasal lining) can swell. It’s this swelling, rather than the mucus produced by your nasal lining, that makes your nose feel blocked.

Sometimes, the infection can spread to your sinuses — small, hollow spaces behind your cheekbones and forehead — causing sinusitis.

Allergic rhinitis

Allergic rhinitis refers to inflammation of your nasal lining when it is irritated by an allergen ie something that triggers an allergic reaction in your nose eg pollen in the case of hay fever, house dust mites, mould and animal dander.

Symptoms of allergic rhinitis, which include a blocked nose, an itchy nose, sneezing, and itchy, red and watery eyes, usually develop within minutes of exposure to an allergen.

A deviated nasal septum

Your nasal septum refers to the cartilage and bone that divides your nasal cavity into two. Your nostrils act as openings to the left and right sides of your nasal cavity.

If this partition is bent to one side, you have a deviated septum. In severe cases, a deviated nasal septum can block one side of your nasal cavity.

Nasal polyps

Nasal polyps are small swellings along your nasal lining, which are not cancerous. These growths hang down from your nasal lining like grapes or teardrops. 

They are usually caused by chronic inflammation of your nasal lining and consequently, are more common if you have asthma, allergic fungal sinusitis or cystic fibrosis. They can also occur if you have a sensitivity to aspirin. 

Swollen adenoids

Adenoids are lumps of tissue at the back of your nose, above the roof of your mouth — you can’t see your adenoids by looking in your mouth. They help fight infection but can swell after an infection or due to an allergic reaction.

Swollen adenoids can, therefore, make your nose feel blocked. However, as adenoids are larger in young children and shrink with age, swollen adenoids are more common in those aged under six years and are rare in adults.

Getting a diagnosis of nasal congestion

If you have frequent or persistent nasal congestion, see your GP

They will ask you about your symptoms and medical history and may perform a physical examination of your nasal cavity using a nasal speculum and a light or an otoscope. This is a small telescope-like device with a light at the end, which is usually used to examine the ear canal.

Depending on the results of your examination, your GP may refer you to a doctor specialising in treating nasal problems (an ENT doctor) for further investigations. This may involve a physical examination using a nasendoscope, another telescope-like device with a light at the end, which allows your doctor to look further into your nose. 

Before examination with a nasoendoscope, your nose will be sprayed with a topical anaesthetic, to make your examination more comfortable, and with a decongestant, to make it easier for your doctor to see inside your nose. 

A nasoendoscope examination is often enough to reach a diagnosis of the cause of your nasal congestion. However, in some cases, further tests — such as a blood test for allergies or a CT scan —  may be needed for more detailed information on the anatomy of your nose and the state of your sinuses. 

Nasal congestion treatment

Treatment for nasal congestion depends on the underlying cause. In some cases, home remedies are enough to relieve your symptoms, while in other cases you may be prescribed medication in the form of nasal wash sprays, steroid sprays or drops, antihistamines or steroid tablets.

If you have more severe symptoms, nasal surgery may be needed.

Treating infections

If you have a blocked nose due to an infection, such as a cold, the flu or coronavirus, it will usually clear on its own in five to 10 days. However, if the infection spreads to your sinuses, causing sinusitis, it can take up to three months for your nasal congestion to clear.

There are home remedies you can try to speed up your recovery from nasal congestion. This includes blowing your nose gently, one nostril at a time, to avoid further irritating your sinuses or causing bleeding. You should also stay hydrated to thin out your mucus and help your body fight off the infection.

If your mucus is especially thick or you have allergic rhinitis, you can try nasal rinsing to ease your symptoms. This involves squirting warm, salty water into your nostrils.

If your sinuses are inflamed, holding a warm flannel on your cheeks can help ease the feeling of fullness in your sinuses.

Finally, dry air can make nasal congestion caused by an infection feel worse. Try to make the air in your home more humid, either by using a humidifier, running a hot shower or boiling water in an open pan.

Treating a deviated nasal septum

In most cases, the symptoms of a deviated septum can be managed using medications, such as decongestants, nasal steroid sprays and antihistamines. However, in more severe cases, your doctor may recommend septoplasty surgery

This is performed under general anaesthesia and is usually a day case, so you can return home on the same day as your surgery. Your surgeon will make a cut along the inside of your nose on one side of your nasal septum, lift off the nasal lining and straighten your septum. The nasal lining will be put back in place and stitched. 

Treating nasal polyps

Nasal polyps can often be shrunk using a steroid nasal spray or drops. However, if this doesn’t resolve your symptoms, your doctor may recommend surgery to remove your nasal polyps.

This is performed under general anaesthesia as a day case, so you can return home on the same day as your surgery. Your surgeon will remove your nasal polyps using a microdebrider — a thin, cylindrical device with small blades that effectively ‘gobble up’ the polyps. If needed, your sinuses may also be opened to remove the ‘root’ of the polyps.

Blocked sinuses

If you have chronic sinusitis, your doctor may recommend functional endoscopic sinus surgery. As with most types of surgery to relieve nasal congestion, this is performed under general anaesthesia as a day case, so you can return home on the same day as your surgery. 

Sinus surgery involves passing an endoscope — a thin, telescope-like device with a light and a camera at the end — into your nose via your nostrils. Then, small instruments are passed into your nose via the endoscope to remove any blockages, inflamed tissue or polyps. 

Your surgeon may also widen the openings between your sinuses and nose so that it's easier for fluid in your sinuses to drain out into your nose. 

Recovering from nasal surgery

It is normal to experience some discomfort, pain and swelling after nasal surgery. However, these side effects are usually mild and pain can be managed with over-the-counter painkillers, such as paracetamol and ibuprofen.

In most cases, you will need to take two weeks off work to fully recover. During your recovery, avoid bending over, swimming, strenuous exercises and heavy lifting.

You will have a follow-up appointment with your surgeon to check on your recovery and whether your nasal congestion has improved.

Risks of nasal surgery

Every surgery comes with risks, such as infection, bleeding and tissue damage. The main complication of nasal surgery is a nosebleed, however, this is usually mild and settles after two to five days. In rare cases, a severe nosebleed may need further surgery.

Author biography

Mr Showkat Mirza is a Consultant ENT Surgeon at Spire Claremont Hospital and at the NHS Royal Hallamshire Hospital and Sheffield Children’s Hospital. Mr Mirza is highly experienced in treating a range of ENT conditions but has a special interest in treating snoring, and nose and sinus diseases.

We hope you've found this article useful, however, it cannot be a substitute for a consultation with a specialist

If you're concerned about symptoms you're experiencing or require further information on the subject, talk to a GP or see an expert consultant at your local Spire hospital.

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